[COMMITTED] ada: Remove unneeded code in handling formal type defaults

["Marc Poulhiès" <poulhies@adacore.com>]

From: Piotr Trojanek <trojanek@adacore.com>

Unneeded code found while experimenting with improved detection of
unreferenced objects.

gcc/ada/

	* sem_ch12.adb (Validate_Formal_Type_Default): Remove call to
	Collect_Interfaces, which had no effect apart from populating a
	list that was not used; fix style.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/sem_ch12.adb | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gcc/ada/sem_ch12.adb b/gcc/ada/sem_ch12.adb
index 2b7833dfdcd..ca0f4913e36 100644
--- a/gcc/ada/sem_ch12.adb
+++ b/gcc/ada/sem_ch12.adb
@@ -17303,13 +17303,11 @@ package body Sem_Ch12 is
 
             else
                declare
-                  Act_Iface_List : Elist_Id;
-                  Iface          : Node_Id;
-                  Iface_Ent      : Entity_Id;
+                  Iface     : Node_Id;
+                  Iface_Ent : Entity_Id;
 
                begin
                   Iface := First (Abstract_Interface_List (Formal));
-                  Collect_Interfaces (Def_Sub, Act_Iface_List);
 
                   while Present (Iface) loop
                      Iface_Ent := Entity (Iface);
-- 
2.34.1